Methanol manufacture from methane via methane to synthesis gas (CO+H2), and then synthesis gas to methanol is the current good, efficient, commercial way to make methanol. It becomes quite economic when performed on a big scale and using natural gas which is relatively free from inert non-hydrocarbon components. Conventional, small plants cannot compete well for capitol which becomes relatively high per unit of methanol produced. System pressure and need for compressors to raise pressure to 700–2500 psig is costly on a small scale. Today, methanol plants of over a billion pounds per year are desired. Whereas, 500 million pounds per year from waste methanol generation is about a maximum. Further, solid waste landfill assay gas will be about 50% carbon dioxide and 5% inerts (mainly nitrogen but with sulfur components, etc.). Carbon dioxide may be conveniently removed by one of several techniques which may also remove sulfur impurities. However, residual N2 in methane is expensive to remove, generally via cryogenic distillation. Thus, a way to use methane without removing nitrogen or doing major compression in making methanol on the scale of solid waste landfills is desirable.
As more and more gas has been discovered in places removed from convenient pipelining, its conversion to methanol—a liquid easily shipped by tanker—has become a major choice use for this high methane natural gas. Three factors impact this product.
This gas product must be imported affecting balance of trade for importing country.
It comes to ports by tanker and requires trans-shipping to inland sites thus adding an additional cost.
Natural gas is not a “regenerable” quantity.
Thus, the conversion of solid waste landfill methane to methanol has some advantage, but the problems of scale, inerts and compression exist.